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1.
EMBO J ; 42(19): e113880, 2023 10 04.
Article in English | MEDLINE | ID: mdl-37602956

ABSTRACT

Dermal Fibroblast Progenitors (DFPs) differentiate into distinct fibroblast lineages during skin development. However, the epigenetic mechanisms that regulate DFP differentiation are not known. Our objective was to use multimodal single-cell approaches, epigenetic assays, and allografting techniques to define a DFP state and the mechanism that governs its differentiation potential. Our initial results indicated that the overall transcription profile of DFPs is repressed by H3K27me3 and has inaccessible chromatin at lineage-specific genes. Surprisingly, the repressive chromatin profile of DFPs renders them unable to reform the skin in allograft assays despite their multipotent potential. We hypothesized that chromatin derepression was modulated by the H3K27me3 demethylase, Kdm6b/Jmjd3. Dermal fibroblast-specific deletion of Kdm6b/Jmjd3 in mice resulted in adipocyte compartment ablation and inhibition of mature dermal papilla functions, confirmed by additional single-cell RNA-seq, ChIP-seq, and allografting assays. We conclude that DFPs are functionally derepressed during murine skin development by Kdm6b/Jmjd3. Our studies therefore reveal a multimodal understanding of how DFPs differentiate into distinct fibroblast lineages and provide a novel publicly available multiomics search tool.


Subject(s)
Chromatin , Histones , Animals , Mice , Chromatin/genetics , Histones/genetics , Histones/metabolism , Jumonji Domain-Containing Histone Demethylases/genetics , Jumonji Domain-Containing Histone Demethylases/metabolism , Cell Differentiation/genetics , Demethylation , Fibroblasts/metabolism
2.
Pediatr Emerg Care ; 39(5): 360-363, 2023 May 01.
Article in English | MEDLINE | ID: mdl-37079552

ABSTRACT

BACKGROUND/OBJECTIVE: Throughout the pandemic, febrile seizures have resulted from infection secondary to severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2). The objective of this study is to determine if there is an increased association between COVID-19 and febrile seizures as compared with other causes of febrile seizures. METHODS: This was a retrospective case control study. Data were collected from the National Institute of Health (NIH) supported National COVID Cohort Collaborative (N3C). Patients from 6 to 60 months who were tested for COVID-19 were included; cases were defined as COVID-19-positive patients whereas controls were defined as COVID-19-negative patients. Febrile seizures diagnosed within 48 hours of the COVID-19 test were considered to be associated with the test result. Patients were subjected to a stratified gender and date matching design followed by a logistic regression controlling for age and race. RESULTS: During the study period, 27,692 patients were included. Of those, 6923 patients were COVID-19-positive, among which 189 had febrile seizures (2.7%). After logistic regression, the likelihood of having febrile seizures concurrently with COVID-19 as compared with other causes was 0.96 ( P = 0.949; confidence interval, 0.81, 1.14). CONCLUSIONS: There were 2.7% of the patients with COVID-19 that were diagnosed with a febrile seizure. However, when subjected to a matched case control design with logistic regression controlling for confounding variables, there does not appear to be an increased risk of febrile seizures secondary to COVID-19 as compared with other causes.


Subject(s)
COVID-19 , Seizures, Febrile , Humans , Seizures, Febrile/epidemiology , Seizures, Febrile/etiology , Seizures, Febrile/diagnosis , COVID-19/complications , COVID-19/epidemiology , Case-Control Studies , Retrospective Studies , SARS-CoV-2
3.
bioRxiv ; 2023 Mar 07.
Article in English | MEDLINE | ID: mdl-36945417

ABSTRACT

Dermal Fibroblast Progenitors (DFPs) differentiate into distinct fibroblast lineages during skin development. However, the mechanisms that regulate lineage commitment of naive dermal progenitors to form niches around the hair follicle, dermis, and hypodermis, are unknown. In our study, we used multimodal single-cell approaches, epigenetic assays, and allografting techniques to define a DFP state and the mechanisms that govern its differentiation potential. Our results indicate that the overall chromatin profile of DFPs is repressed by H3K27me3 and has inaccessible chromatin at lineage specific genes. Surprisingly, the repressed chromatin profile of DFPs renders them unable to reform skin in allograft assays despite their multipotent potential. Distinct fibroblast lineages, such as the dermal papilla and adipocytes contained specific chromatin profiles that were de-repressed during late embryogenesis by the H3K27-me3 demethylase, Kdm6b/Jmjd3. Tissue-specific deletion of Kdm6b/Jmjd3 resulted in ablating the adipocyte compartment and inhibiting mature dermal papilla functions in single-cell-RNA-seq, ChIPseq, and allografting assays. Altogether our studies reveal a mechanistic multimodal understanding of how DFPs differentiate into distinct fibroblast lineages, and we provide a novel multiomic search-tool within skinregeneration.org.

4.
J Invest Dermatol ; 142(7): 1812-1823.e3, 2022 07.
Article in English | MEDLINE | ID: mdl-34922949

ABSTRACT

One of the keys to achieving skin regeneration lies within understanding the heterogeneity of neonatal fibroblasts, which support skin regeneration. However, the molecular underpinnings regulating the cellular states and fates of these cells are not fully understood. To investigate this, we performed a parallel multiomics analysis by processing neonatal murine skin for single-cell Assay for Transposase-Accessible Chromatin sequencing and single-cell RNA sequencing separately. Our approach revealed that fibroblast clusters could be sorted into papillary and reticular lineages on the basis of transcriptome profiling, as previously reported. However, single-cell Assay for Transposase-Accessible Chromatin sequencing analysis of neonatal fibroblast lineage markers, such as Dpp4/Cd26, Corin, and Dlk1 along with markers of myofibroblasts, revealed accessible chromatin in all fibroblast populations despite their lineage-specific transcriptome profiles. These results suggest that accessible chromatin does not always translate to gene expression and that many fibroblast lineage markers reflect a fibroblast state, which includes neonatal papillary fibroblasts, reticular fibroblasts, and myofibroblasts. This analysis also provides a possible explanation as to why these marker genes can be promiscuously expressed in different fibroblast populations under different conditions. Our single-cell Assay for Transposase-Accessible Chromatin sequencing analysis also revealed that the functional lineage restriction between dermal papilla and adipocyte fates is regulated by distinct chromatin landscapes. Finally, we have developed a webtool for our multiomics analysis: https://skinregeneration.org/scatacseq-and-scrnaseq-data-from-thompson-et-al-2021-2/.


Subject(s)
Fibroblasts , Single-Cell Analysis , Animals , Chromatin/genetics , Chromatin/metabolism , Fibroblasts/metabolism , Mice , Skin , Transposases/metabolism
5.
Cell ; 184(15): 3852-3872, 2021 07 22.
Article in English | MEDLINE | ID: mdl-34297930

ABSTRACT

Fibroblasts are diverse mesenchymal cells that participate in tissue homeostasis and disease by producing complex extracellular matrix and creating signaling niches through biophysical and biochemical cues. Transcriptionally and functionally heterogeneous across and within organs, fibroblasts encode regional positional information and maintain distinct cellular progeny. We summarize their development, lineages, functions, and contributions to fibrosis in four fibroblast-rich organs: skin, lung, skeletal muscle, and heart. We propose that fibroblasts are uniquely poised for tissue repair by easily reentering the cell cycle and exhibiting a reversible plasticity in phenotype and cell fate. These properties, when activated aberrantly, drive fibrotic disorders in humans.


Subject(s)
Disease , Fibroblasts/metabolism , Health , Animals , Cell Lineage , Humans , Molecular Targeted Therapy , Signal Transduction
6.
J Pediatr Hematol Oncol ; 42(6): 375-380, 2020 08.
Article in English | MEDLINE | ID: mdl-32569034

ABSTRACT

Sickle cell disease (SCD) can lead to potentially devastating complications that occur secondary to vaso-occlusion. Current national clinical guidelines are largely based on expert opinion, resulting in significant variation of management. Provider awareness regarding emergency department (ED) management of vaso-occlusive crises (VOC) remains unknown. A 23-question assessment of VOC management was administered to all eligible ED providers at Riley Hospital for Children between September and November 2018. Univariate analyses were performed to evaluate responses between groups. Of 52 respondents comprised of ED staff attendings (27%), resident trainees (58%), and ED nurses (15%), the majority were not aware of SCD management guidelines being available. Approximately 54% of providers endorsed a high comfort level in managing VOC, with staff and nurses more likely to report this than trainees (P=0.02). Less than 10% of all providers knew the recommended timeframe from triage to initial medication administration. Prolonged time between pain assessments was reported by 25% of providers with a high comfort level in managing VOC, which was similar to providers with a lower comfort level (13%, P=0.217). Only one fourth of all respondents appropriately did not use vital signs as an indication of a patient's pain level, and >10% reported not utilizing patient-reported pain scores. This was not significantly different between provider comfort levels (P=0.285 and 0.412, relatively). Our results suggest education regarding recommended practices was inadequate regardless of reported provider comfort. Further provider education and/or standardized ED VOC management guidelines may serve as areas for improvement in SCD care.


Subject(s)
Anemia, Sickle Cell/complications , Emergency Service, Hospital/statistics & numerical data , Health Personnel/psychology , Pain Management/methods , Pain/prevention & control , Acute Disease , Adult , Child , Cross-Sectional Studies , Female , Humans , Male , Pain/etiology , Pain Measurement , Surveys and Questionnaires
7.
Front Plant Sci ; 8: 1045, 2017.
Article in English | MEDLINE | ID: mdl-28674546

ABSTRACT

Iron (Fe) is an essential mineral nutrient and a metal cofactor required for many proteins and enzymes involved in the processes of DNA synthesis, respiration, and photosynthesis. Iron limitation can have detrimental effects on plant growth and development. Such effects are mediated, at least in part, through the generation of reactive oxygen species (ROS). Thus, plants have evolved a complex regulatory network to respond to conditions of iron limitations. However, the mechanisms that couple iron deficiency and oxidative stress responses are not fully understood. Here, we report the discovery that an Arabidopsis thaliana monothiol glutaredoxin S17 (AtGRXS17) plays a critical role in the plants ability to respond to iron deficiency stress and maintain redox homeostasis. In a yeast expression assay, AtGRXS17 was able to suppress the iron accumulation in yeast ScGrx3/ScGrx4 mutant cells. Genetic analysis indicated that plants with reduced AtGRXS17 expression were hypersensitive to iron deficiency and showed increased iron concentrations in mature seeds. Disruption of AtGRXS17 caused plant sensitivity to exogenous oxidants and increased ROS production under iron deficiency. Addition of reduced glutathione rescued the growth and alleviates the sensitivity of atgrxs17 mutants to iron deficiency. These findings suggest AtGRXS17 helps integrate redox homeostasis and iron deficiency responses.

8.
Small ; 12(5): 623-30, 2016 Feb 03.
Article in English | MEDLINE | ID: mdl-26662357

ABSTRACT

Biological responses to photothermal effects of gold nanoparticles (GNPs) have been demonstrated and employed for various applications in diverse systems except for one important class - plants. Here, the uptake of GNPs through Arabidopsis thaliana roots and translocation to leaves are reported. Successful plasmonic nanobubble generation and acoustic signal detection in planta is demonstrated. Furthermore, Arabidopsis leaves harboring GNPs and exposed to continuous laser or noncoherent light show elevated temperatures across the leaf surface and induced expression of heat-shock regulated genes. Overall, these results demonstrate that Arabidopsis can readily take up GNPs through the roots and translocate the particles to leaf tissues. Once within leaves, GNPs can act as photothermal agents for on-demand remote activation of localized biological processes in plants.


Subject(s)
Arabidopsis/drug effects , Arabidopsis/radiation effects , Gold/pharmacology , Light , Metal Nanoparticles/chemistry , Temperature , Acoustics , Arabidopsis Proteins/genetics , Arabidopsis Proteins/metabolism , Biological Transport/drug effects , Biological Transport/radiation effects , Gene Expression Regulation, Plant/drug effects , Gene Expression Regulation, Plant/radiation effects , Genes, Plant , Imaging, Three-Dimensional , Lasers , Plant Leaves/drug effects , Plant Leaves/metabolism , Plant Leaves/radiation effects , Plant Vascular Bundle/drug effects , Plant Vascular Bundle/radiation effects
9.
J Biol Chem ; 286(23): 20398-406, 2011 Jun 10.
Article in English | MEDLINE | ID: mdl-21515673

ABSTRACT

Global environmental temperature changes threaten innumerable plant species. Although various signaling networks regulate plant responses to temperature fluctuations, the mechanisms unifying these diverse processes are largely unknown. Here, we demonstrate that an Arabidopsis monothiol glutaredoxin, AtGRXS17 (At4g04950), plays a critical role in redox homeostasis and hormone perception to mediate temperature-dependent postembryonic growth. AtGRXS17 expression was induced by elevated temperatures. Lines altered in AtGRXS17 expression were hypersensitive to elevated temperatures and phenocopied mutants altered in the perception of the phytohormone auxin. We show that auxin sensitivity and polar auxin transport were perturbed in these mutants, whereas auxin biosynthesis was not altered. In addition, atgrxs17 plants displayed phenotypes consistent with defects in proliferation and/or cell cycle control while accumulating higher levels of reactive oxygen species and cellular membrane damage under high temperature. Together, our findings provide a nexus between reactive oxygen species homeostasis, auxin signaling, and temperature responses.


Subject(s)
Arabidopsis Proteins/biosynthesis , Arabidopsis/enzymology , Arabidopsis/growth & development , Gene Expression Regulation, Enzymologic/physiology , Gene Expression Regulation, Plant/physiology , Glutaredoxins/biosynthesis , Hot Temperature , Indoleacetic Acids/metabolism , Arabidopsis/genetics , Arabidopsis Proteins/genetics , Biological Transport/physiology , Cell Cycle/physiology , Glutaredoxins/genetics , Homeostasis/physiology , Mutation , Oxidation-Reduction , Reactive Oxygen Species/metabolism , Signal Transduction/physiology
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